For each colored layer, mix one box of red or blue jello with ½ envelope of unflavored gelatin, add 1 cup of boiling water, and stir to dissolve. For the white, mix sweetened condensed milk with 1 cup of boiling water. In a separate small bowl, sprinkle 2 envelopes of unflavored gelatin over ½ cup of cold water. Let stand a few minutes and then add ½ cup of boiling water to dissolve the gelatin. Add to the milk mixture and stir to combine. You should have 3 cups of this, so measure out one cup for each white layer.

The trick is to make up each batch of jello, let it cool in the mixing bowl to room temperature !!! , pour it into the 9x13 pan (onto any previous layers that have had a chance to set up), and let it refrigerate for 15-20 minutes between each layer. Cooling the liquid to room temp is crucial so that it doesn't melt into the previous layers. At the same time, liquid jello can't sit out forever... my last blue layer tried to set up in the mixing bowl, but a zap in the microwave fixed that. Also make sure your pan is level in the refrigerator, so that your layers are level!

Next up I want to try Rainbow Jello:I think it's super-geeky-cool how just the 3 primary colors, stacked and translucent, can make the whole spectrum appear! (photo courtesy of Do Better)